The present invention relates to a motorized drive for a tarpaulin closure system used with an open box-like container such as a truck box or storage bin. A tarpaulin system suitable for the application of the present invention is disclosed in my Canadian Patent 1,132,168 and corresponding U.S. Pat. No. 4,484,777. My aforementioned patents disclose a truck box having parallel side walls joined by transverse front and back end walls, with a flexible fabric cover fixed at one lateral edge to one side wall, and attached at the opposite edge lateral to a roll tube which is rotatable from side-to-side along the top surfaces of the front and back end walls of the truck box to permit winding and unwinding of the fabric from the roll tube thereby opening and closing the cover of the box structure. The foregoing roll tube is operated manually by a shaft crank connected to the roll tube by a universal joint at the back end wall of the box. Different features of lateral roll tube tarpaulin systems are disclosed in U.S. Pat. Nos. 3,384,413 to Sargent; 4,302,043 to Dimmer; and 4,505,512 to Schmeichel and Canadian Patent 1,134,411 to Block.
It has been recognized that an automatic deployment means for a lateral roll tube system, which can be rapidly operated from a remote position such as the cab of a truck or the like, is desirable. U.S. Pat. Nos. 4,095,840 to Woodard and 4,341,416 to Richard disclose motor actuated systems for deploying tarpaulin covers from front to back of a truck box. U.S. Pat. No. 4,673,208 to Tsukamoto discloses a hydraulic system for side-to-side deployment of a canvass system. Canadian Patent 1,243,062 to Hawken and U.S. Pat. No. 4,518,193 to Heider disclose electric systems for side-to-side deployment of a roll tube and canvass tarpaulin system. Each of U.S. Pat. Nos. 4,518,193 and 4,673,208, and Canadian Patent 1,243,062 disclose a complex drive system involving track mechanisms, and in the case of U.S. Pat. No. 4,673,208 a rotational drive for the roll tube which is not coordinated with the rate of lateral translation of the roll tube. In the case of Canadian Patent 1,243,062, the track system for mounting the electric motor is open to the elements and susceptible of binding from airborne debris.
It is an object of the present invention to provide a simplified motor driven box cover deployment system with a minimum of moving parts. It is also an object of the invention to provide a system for maintaining adequate tautness in the tarpaulin or cover during deployment and to ensure that the roll tube remains parallel to the side walls. It is a further object of the invention to provide a system which correlates the lateral movement of the roll tube with the rate of deployment of the fabric cover. It is also an object of the invention to provide a motorized cover deployment system which can be operated remotely.